Odd Comet Compass Question...

[Macs]

Hi,
Been navigating "Great Circle" lately, and wanted to use the Comet for a Pacific Ocean or maybe African continent crossing using celestial navigation, dead reckoning and pilotage (little or no radio navigation to be used). I am not sure if the compass in the excellent Comet 4 is always corrected to magnetic or can it be "unslaved" to run in gyro-only mode? I can still fly with magnetic correction, but flying true makes it somewhat easier due to variation. Thanks in advance for your help,
regards,
Macs

[cstorey]

I think that when you refer to "compass" you are actually referring to the Directional Gyro. In the real world these are always set to a magnetic heading, because either they are slaved to a compass by a magnesyn or similar arrangement , or they are reset manually to the magnetic compass every 15 minutes or so. IIRC there is an option in the settings of FS to have the gyro drift as it does in real life, by about 15 degrees per hour, or to eliminate drift by simulating a slaving arrangement. However, you are always going to have to deal with variation, and of course this varies according to the triangular relationship between your position , that of the magnetic pole, and that of the true north pole , together with local magnetic anomalies . The variation is now fairly readily available on the internet for most parts of the world by viewing the AIPs for relevant countries, and if you remember the adage " variation west, magnetic best, variation east, magnetic least" you will know to add west variation to your desired true couse to get the magnetic course , and to subtract east variation

[SkippyBing]

Interestingly in RN aircraft at least they have a compass controller where you dial in the magnetic variation which then gives you the true heading on all the repeaters, radar displays etc. The latest version of the Lynx even carries a worldwide variation database to save looking things up, it helps dealing with ships who operate in true as well.
I think FS might have a setting to choose real or magnetic North if you poke around, if not you could write an XML gauge to give you true North as it's one of the sim variables.

[Macs]

I think that when you refer to "compass" you are actually referring to the Directional Gyro. In the real world these are always set to a magnetic heading, because either they are slaved to a compass by a magnesyn or similar arrangement , or they are reset manually to the magnetic compass every 15 minutes or so. IIRC there is an option in the settings of FS to have the gyro drift as it does in real life, by about 15 degrees per hour, or to eliminate drift by simulating a slaving arrangement. However, you are always going to have to deal with variation, and of course this varies according to the triangular relationship between your position , that of the magnetic pole, and that of the true north pole , together with local magnetic anomalies . The variation is now fairly readily available on the internet for most parts of the world by viewing the AIPs for relevant countries, and if you remember the adage " variation west, magnetic best, variation east, magnetic least" you will know to add west variation to your desired true couse to get the magnetic course , and to subtract east variation

Cstorey,
Thanks for your reply. I was wondering if you could "unsalve" the gyro-compass in the Comet, like it works in the Cessna 172 (where you manually correct for gyro-drift). One of the routes I wanted to fly involves flying in the arctic regions so magnetic compass unreliability, dip, extreme variation and meridian convergence make it very hard to navigate using "older" means (FS can be surprisingly good in simulating this believe it or not). Now, if you have a GPS or follow VOR radials with an AP there is no issue.
I have been been successfully navigating with other aircraft where the gyro compass is not "slaved" for the above mentioned cases. It would be even nicer if the Comet had a feature to correct for latitude also in non-magnetic mode (I wonder if they had them?). When flying Grid or even true if you wanted, you can estimate true courses with a sun-compass gauge (available at most FS sim sites) as well as with the bubble sextant for FS. Anyway, thanks for your reply,
regards,
Macs

[Macs]

There actually is a Mag-Gyro mode selection possibility in the Comet> It appears that it is not implemented in FS, but the main panel has it in the VC. It woudl be cool if in the future it could be implemented
regards,
Macs